Microfluidic Device Manipulates Droplets with Ultrasound: May Revolutionize Diagnostics

Microfluidic devices are a major topic of research lately, partly because they have the potential to scale down existing devices and to make new diagnostic tools possible.

Typically, microfluidic systems consist of scaled-down versions of conventional tubes, pumps, and valves. While effective for many applications, conventional components often get quickly clogged and lose their function when working with complex biological fluids such as blood. This is because blood, and other bodily fluids, contain a variety of components, such as proteins, that adhere to surfaces.

Now researchers at Duke University are showing off a new microfluidic system that works entirely differently, one that freely moves liquid droplets, mixes them, and splits them without any tubes, pumps, or valves. Moreover, because all this happens on a layer of oil, the droplets can be manipulated so they don’t leave any traces behind, significantly increasing the lifetime of such microfluidic devices and avoiding any cross-contamination in the process.

The technology utilizes a small pool of inert oil below which piezoelectric transducers create microscopic waves. These waves are carefully controlled by a computer to gently push droplets placed on top of the oil. The vibrations can be used to bring droplets together and to break them apart without splashing any excess around the pool of oil.

This latest advance should help to turn into reality microfluidic devices that were not possible with previous approaches. Additionally, small scale experiments that were previously exceedingly difficult to perform will now be routine thanks to this new way of manipulating liquids.